Flyman2456 Posted May 8, 2021 Report Share Posted May 8, 2021 We're replacing my trim wheel bushing this annual for excessive wobble. Since the sprockets have to be removed, thought it would be a good time to do Service Bulletin M20-154 (Retrofit of New Sprockets). 1. Are the roll pins really the only thing that transfers the load to the shaft?? There's no key-way as I would expect. The old sprockets also have a setscrew but it doesn't appear to penetrate the shaft.. 2. The new sprockets that came with the service bulletin kit from Lasar don't have the setscrew holes (service bulletin says to install setscrews on new sprockets so wondering if I got the correct parts)? Thanks in advance. SBM20-154.pdf Quote Link to comment Share on other sites More sharing options...
PT20J Posted May 8, 2021 Report Share Posted May 8, 2021 My M20J just has the roll pin. 1 Quote Link to comment Share on other sites More sharing options...
Flyman2456 Posted May 8, 2021 Author Report Share Posted May 8, 2021 Interesting, I'm sure the shear loads on the pin are pretty low but still...would have thought there would be a tab/keyway. Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted May 10, 2021 Report Share Posted May 10, 2021 A steel rolled pin in shear if the parts are close tolerance is actually very strong, the airplane is held together by aluminum pins in shear and steel is a lot stronger. 1 Quote Link to comment Share on other sites More sharing options...
PT20J Posted May 10, 2021 Report Share Posted May 10, 2021 On 5/7/2021 at 6:48 PM, Flyman2456 said: Interesting, I'm sure the shear loads on the pin are pretty low but still...would have thought there would be a tab/keyway. Hey, if you are worried about that, don't ever look at the bolts that hold your engine mount to the firewall, or the bolts that hold the empennage to the tail cone 2 1 Quote Link to comment Share on other sites More sharing options...
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